<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
  <style>
    div{
      width: 100px;height: 100px;
      border:1px solid red;
    }
    div:hover{
      /*margin-top: 20px;
      margin-left: 20px;*/
      /*设置相对定位,可以实现元素层叠效果*/
      position: relative;
      top: 20px;
      left: 20px;

    }
  </style>
</head>
<body>
  <div>div1</div>
  <div>div2</div>
  <div>div3</div>
</body>
</html>